Chernobyl 40 Years On: Legacy of the World’s Worst Nuclear Disaster

0:00And now a word from our sponsor South by Southwest London. Imagine a future where things just make sense. In the 1700s we had canals, in the 1800s the railways, then telecom, fibre optic, and now? In a world that's more unsure than ever before, we need the answers. South by Southwest London presents over 900 speakers, 200 music artists, and 100 films in one location in June. To find out how they merge together and shape the future in person, visit southbysouthwestlondon.com. That's s-x-s-w-london.com. The world's worst nuclear disaster happened at 1.23am on April 26, 1986. Reactor number four at Chernobyl Nuclear Power Station in Ukraine blew up, sent a massive amount of radioactive material into the sky and into the surrounding area.

0:48That's what we're getting into on this episode of The World, the Universe and Us. I'm Rowan Hooper. We're exploring the legacy of Chernobyl, what we've learned from it about radiation, ecology and human behaviour and in particular maybe how it skewed the public understanding of nuclear power. We're also going to be drinking atomic brandy made from radioactive apples grown in not the exclusion zone, it's the what zone? We call it the second zone or the zone of obligatory resettlement which was supposed to be abandoned but wasn't fully abandoned. atomic brandy made from radioactive apples but completely safe to do all this i'm joined by reporter matt sparks you've recently been to chernobyl to the exclusion zone seen the site and by professor jim smith of the university of portsmouth jim's a professor of environmental science specializing in radiation pollution and the author of a book called chernobyl catastrophe and consequences welcome both thank you so look i just want to start quickly with the the war, the Russian war on Ukraine at the moment, because the Russians captured Chernobyl in 2022.

1:54It was then recaptured by Ukraine, but it was hit by a missile last year. Is it safe? You've just come back. What was it like there? Well, Chernobyl is just a few kilometers from the Belarusian border, which is a country that's allied to Russia, essentially. So it's extremely close to the border of the opposing side in the war. So it was also the route that the Russian forces took to try to get to Kyiv. Exactly. So it was a really heavily contested site in the first few days of the war. Russians occupied it for a couple of months and then the Ukrainian forces pushed back. So now you can imagine it's essentially a military base, a blockade to stop any future invasion.

2:41and also it's the route for an awful lot of the drones that Russia fires towards the capital. So there's also anti-aircraft, anti-drone protection. So it's locked down much more safely than perhaps it was before. Yeah, it feels like a military base really. Okay. And Jim, you've been going to Chernobyl since when? 1990, is it? 1990, I started my PhD in applied maths, trying to model where the radioactivity went in the English Lake District. So we got some fallout from Chernobyl in parts of Wales, parts of Scotland, in the north of England. I first went to Ukraine, Belarus and Russia and the exclusion zone in 1994.

3:22And more or less, up until COVID, I was going twice a year to do field work, to have meetings and so on in the exclusion zone in some of the other abandoned areas in Belarus and Russia. Yeah. We're going to talk about ecology and rewilding of the area in a bit. But how did it change in those years? Because you went pretty kind of soon after the disaster, really, and then a long time after that. Yeah. I mean, it was a very strange experience for me because at the time I was a physicist and mathematician and I wasn't a specialist in radiation risk. And I remember my boss said, oh, would you go and do some field work?

4:02We had joint European projects with scientists in Russia, Belarus and Ukraine. And he said, I'm sending you off on a field trip to the Chernobyl exclusion zone. And I thought, is this OK? And I said, is it OK? And he said, oh, ring this guy at the National Radiological Protection Board, which is what now the Health Protection Agency is. And so I rang this guy and he said, how long are you going for? And I said, two weeks. And he said, oh, you'll be fine. and so that reassured me slightly but even so when work you know of course my belarusian colleagues and ukrainian colleagues they were totally relaxed about it because they'd been there in the early days after the accident but i still found it slightly strange and unnerving to be there now that i know an awful lot more i know it was absolutely fine but at that time for me as a kind of young postdoctoral student then i found it quite a scary experience exciting as well yeah very exciting yeah what i didn't realize uh is that the explosion happened because of a safety test that went wrong so it wasn't like fukushima where something external impinged on the reactor and you know made it blow up so it wasn't that that necessarily that the reactor was unsafe it was the safety test went wrong.

5:19Yeah, it's a long and complicated story and still contested actually what caused the actual accident. But it was, as is often the case with these sort of things, it was various different things coming together, which with, in retrospect, and not that surprising due to the way that the Soviets ran their reactors, the culture of secrecy surrounding nuclear, even in the nuclear industry. So there had been a similar, not nearly as serious, accident at the Leningrad nuclear power station before Chernobyl happened. But the findings of that, which was that that type of reactor wasn't a stable reactor design under certain conditions, the findings of that accident weren't publicised even within the nuclear industry.

6:10so the plant operators at chernobyl didn't know what had happened at leningrad and hadn't learned from that and the whole system hadn't learned from that but yeah you're right it was a safety experiment that went wrong and i say with retrospect but actually you know the people in the control room at the time of the accident the story i've heard many stories the story i've heard is that the guy who was actually operating the control rods and the reactor itself he said we shouldn't be doing this because they'd got they were looking at the how the reactor performed under certain very low power conditions under which this design of this flawed reactor design was basically not safe it had certain properties in which it could have a runaway chain reaction and they'd got the reactor in this low power state but it wasn't stable when they did it for various reasons which i can't really go into but it was it was an unstable reactor before they started the experiment the guy at the control rods from what i heard said let's stop it shut down the reactor start it again get it in the right conditions and run the experiment then but the guy running the control room who wasn't as expert as the people at the controls he had various personal incentives he wanted to get it done the soviet system was very hierarchical actually and although it was communist it was very hierarchical and he said just do it yeah and more or less bullied them into going ahead and of course 30 seconds later they went you know they went ahead 30 seconds later the reactor exploded wow um and tell us about a little bit about what What happened to the material that was cast out?

7:59Maybe especially about what's still there now, because some of the stuff that's got a very long half-life that we still need to worry about now. So the explosion differed from Fukushima. So Fukushima was what they call a loss of coolant accident. So there wasn't enough cooling going into the reactors, the three reactors that exploded. That led to a partial meltdown of the reactor core, which created temperatures which produced hydrogen gas. The hydrogen gas leaked into the reactor buildings and that's what caused those very dramatic explosions of the reactor buildings. Chernobyl was different in that it was an explosion within the reactor core, which was sufficiently powerful to knock the giant container.

8:45You know, they have the enormous thick concrete and steel structures around nuclear reactor cores, enough to flip the lid of the reactor and you can actually see in the pictures of the destroyed reactor like a coin almost flipped into the air and landed back on its side so that the initial explosion and the fire which lasted for 10 days because it was a graphite moderated reactor the graphite itself set on fire that spread radioactivity as we know around around Europe. Matt, when you went there, you met scientists that still work there. And I think a lot of people will be surprised, maybe, that there's a lot of science.

9:25I mean, I know the war has interrupted it. But disregarding that part of it, so much science has been going on at Chernobyl, at the site. A huge amount, yeah. There were all sorts of organisations, universities around the world sending researchers there. The war has essentially put a stop to most of that. But it's still a busy site. I mean, you've got all the military workers, for one thing, but there's engineers, decommissioning engineers. It's a sort of, it's a bustling place that it's not, this idea of it being an abandoned wasteland, it's a town, really. And like, you know, we said that we didn't learn from the accident at Leningrad.

10:06In the old Soviet days, that wasn't, but what we are doing now is learning in great detail. And that's why there were so many scientists there. Yeah yeah and you know Jim's the expert here but from what I understand we've learned an awful lot about how these sorts of accidents happen, the result of them and how to sort of mitigate the effects of radiation you know of this contamination. So it has it was likened to the aviation industry to me you know we're we're now in a position where we actually learn lessons and change the industry because things like Chernobyl they're not lessons you want to learn more than once are you yeah the other thing that really surprised me and so you would have seen this in your earlier visits to to Chernobyl was that even after the react so reactor four was the one that blew up but reactors one two and three just keep them going they kept going and three took a while because three is the one next door to reactor floor that exploded but it did keep going and I think it was I can't remember which one I think it was maybe reactor one kept going until the year 2000.

11:11Yeah. And it was sort of under slight duress that Ukraine closed it. Of course, there were, because we now knew that that kind of reactor design had this inherent instability, there were problems with how the control rods were designed, how the emergency scram, how fast the control rods were inserted into the reactor. So they just fell under gravity and it was a very big reactor core. So it took something like 30 seconds for the control rods to fully be inserted in the core, even under emergency conditions. So subsequent, all the reactors of that design had improvements in their safety in general.

11:54But Ukraine didn't really want to shut down all of Chernobyl in the year 2000, but there was a kind of international effort to say, okay, we'll help you with support of decommissioning of the site, with other energy sources, if you shut down the last Chernobyl reactor. And that's partly symbolic, I think, but that's what happened. And take us through, obviously they encased Reactor 4 in this sarcophagus. There's been since this new thing they're building over the top to contain it. But whilst the other reactors are working and all the scientists that are there, plus people going into the Reactor 4 area, like, how is it all safe?

12:37with this burning mass of radioactive plutonium and uranium underneath the sarcophagus. Well, like you say, it is shrouded by two layers, essentially, of protection. You've got this big Soviet concrete sarcophagus, huge lump of concrete. And over that, you've got the modern, new safe confinement. And, I mean, it is sealed up, essentially, isn't it? Yeah. And essentially, almost all of the reactor core melted down. melted, you know, that famous thing we call the China syndrome. It melted down through the bottom of the reactor, and it's somewhere there in the basement. And it took actually the Soviets a little while to figure out where it was, because nobody could go in there in the immediate period.

13:24And so it's there in the basement, still very, very radioactive. But, as we know, shielding distance reduces radioactive doses, radiation doses even from the very penetrating gamma rays it does reduce the doses so you can go into the sort of reactor four control room you can go in the next door reactor three without really getting a huge radiation dose yeah so work could carry on on site and the site seems surprisingly normal yeah when you go and visit except for this giant what was the sarcophagus the giant concrete building and now what is the new safe confinement so the worry has been about not so much the core but the stuff that fell down around the the region um so what sort of radiation radioactive particles were that and and that goes into the soil and then into tell us about that so fresh nuclear fuel when it's put in a reactor is in that type of reactor is is mainly uranium and it sounds strange to say but it isn't that radioactive it's where it becomes more as it gets older it gets more and more radioactive because it becomes spent fuel so the uranium breaks down into what we call the fission products the things that happen when nuclear fission happens and it produces radioactive elements like radioactive cesium radioactive iodine some of the longer lived plutonium americium so that's what we're concerned about in the exclusion zone so within sort of 10 kilometers of the reactor is where most of the kind of dust from the accident was so that includes particles of nuclear fuel so the the half spent or spent fuel with tiny microscopic particles of fuel were spread around in that area.

15:19Further afield, we got the more volatile radioactive elements like radioactive iodine. So radioactive iodine has a very short half-life. So every eight days after the accident, half of it disappeared. So a few weeks after the accident, all the iodine was gone. But in that time, it spread around Europe, and radioactive iodine is very mobile in the environment. So the early problems that we saw after Chernobyl were mainly due to iodine. Another isotope called cesium, a large proportion of the cesium that was in the reactor core, was spread in the exclusion zone further afield. In the UK, it rained on upland areas when the cloud passed, and that washed out the cesium and iodine onto the land.

16:07and we might not remember but there were controls on sheep movement in a number of farms in up to hundreds of farms in the UK to stop the contaminated meat getting in the food chain yeah and was that precautionary or was it really necessary to do that that's a good question both really I think because there is this massive fear isn't there there is and we'll get into that in a sec but but the other thing is in the exclusion zone so people moved were forced out now it's basically this lovely big nature reserve now you know it's not like this this glowing wolves or any mutated creatures running around it's it's kind of looks like a wonderful wild wilderness yeah i mean we haven't seen any mutants no that doesn't mean to say there aren't you know science In science, we can never prove a negative.

17:02We can't prove that a non. If there were, they would probably get predated out of the system. But it's very unlikely, I think. So the mutation, radiation causes mutation. There are some hot spots in the zone, like the cooling pond, the reactor where we've worked on the fish and the insects. The red forest, which is the forest that was so intensely radioactive, radioactive, the trees died in the weeks after the accident. So there are those hotspots which are a relatively small part of the whole zone. So there is, you know, we know radiation causes DNA damage, so there is DNA damage going on. But apart from that, we found it really hard to see what I would call the subtle effects of radiation on organisms.

17:50So for example, we studied fish in the cooling pond and some other lakes in the area we think we've seen an association between the radiation and the development of reproductive organs in one type of fish it doesn't mean to say they can't reproduce but it's had that subtly we think it's had that subtle effect but even we're not sure after spending three years trying to find it yeah we're not sure radiation's the causal factor right and very often you'll see lots of research about chernobyl and the effects on wildlife at Chernobyl but very few of them and actually probably none can really say radiation is causing the effect and what tends to happen is a lot of scientists have of course gone to the zone to look at the animals I look at the plants and they find something different between a contaminated area and a less contaminated area and the natural assumption is that's caused by radiation but natural ecosystems are really complicated and teasing out that causal effect of radiation has been really hard yeah but on the on the other side as you've referred to in terms of the populations of animals the exclusion zone is now much more abundant and diverse an ecosystem than it was before the accident yeah well as for teasing out the effect of radiation and as you say we we can't be sure what effects it's had yet we can be sure that other we know other environmental pollutants do have an effect say on on fish sex development and stuff right and yet we're not up in arms about that but but this gets to the point of the fear factor of radiation and that and perhaps the overhype that there is so look you've worked on this for years what's your theory on why there is this fear about it i mean radiation ticks all the boxes of what scares us there's been research on this psychologists have looked at it and so it ticks the box of it's something we can't see it's something technological that most of us unless you've spent a lifetime studying it most of us don't really understand when we think of chernobyl and radiation we think of the terrible events of the night of the accident we think about the atomic bombs on hiroshima and nagasaki right and the things that you know it leads to cancer which is something we're all scared about yeah and and and mutation these things so it ticks every box of what scares us and i think that might be behind this our difficulty in overcoming this fear of of radiation yeah i mean i do think though it irritates me it must irritate you that there is a lot of controversy about the the total number of deaths caused by chernobyl but the fact is that fossil fuels kill millions of people a year through air pollution yes and yet you know where is the fear and outrage about that i agree completely i think um And we mentioned in the feature that I wrote when I got back that the death toll from Chernobyl is completely, you know, pales into insignificance when you look at the deaths from fossil fuels that were used as a result of the tarnished reputation of nuclear power from Chernobyl.

21:17So, as you say, every year, the scale of deaths from fossil fuels is far bigger than Chernobyl over the last four decades. And then when Fukushima happened, it was much less of a disaster in terms of risk to human life than Chernobyl. And then, you know, that had knock-on effects. The Japanese, you know, scaled down their nuclear power, the Germans did. So, you know, there's this massive sort of safety barrier we need to get over for nuclear that isn't there for fossil fuel energy. I think, I mean, I've said before that if we applied the same safety constraints to fossil fuels as we did to nuclear, then we would shut down every fossil fuel plant tomorrow.

22:03The picture is quite complicated, I think. When you make decisions about energy, we tend to think, let's try and be safe. But there are no safe decisions. There are no, you know, we know that wind farms cause deaths of construction workers. We know windmills use lots and lots of rare earth metals in their magnets and their electronic systems. Solar panels, the majority in the world, are made under really difficult conditions by minority groups in China. The rare earth and heavy metals that are used in renewables are mined in sometimes very horrendous conditions in some countries like the Congo.

22:46and so when we make one decision about energy so we say let's not have nuclear let's build more wind farms more batteries to store the energy all these things it's not a totally safe option and that was really illustrated after fukushima when germany made the decision to stop their nuclear program early there was a calculation that so what the germany did was it did increase its renewables, which is great, but it didn't shut down its coal-fired power stations. And they're the worst. They're just the worst for CO2. So the calculation I saw was that there were something like 36 million tons of extra CO2 put in the atmosphere every year because the nucleosites were shut down.

23:34There were something like 1 ,000 air pollution deaths every year because the nucleosites were put down. And these are all calculations, but it illustrates that we don't have risk-free options. Every option that we take, so if we shut down a nuclear power station or fail to build one, we're cutting off any potential risk of an accident, of course. But on the other side, usually what we do is we lock in either gas or coal. Yeah, and that, as we've said, has its own terrible consequences. Matt when you were there you visited some people who've moved back into the exclusion zone and even you know you got invited to their house what was that like what are they tell us about what they're doing there and why they wanted to move back yeah so there's there's dozens of uh of settlers in in Chernobyl town still and one couple who I I went to meet had lived there the gentleman was taken there as a baby in the wake of World War II when there were no apartments in Kyiv and they settled there and he's lived his entire life there and you know a wonderfully cute house lovely vegetable garden this this couple have lived there for the best part of 80 years and uh it's striking that they've lived a relatively normal life uh amidst all all of this uh this chaos really you know they they left for just a month when the accident happened and they were sort of forced to resettle and then just sort of snuck back in as many people did.

25:03But the numbers of settlers are dwindling now. Young people don't necessarily want to live there. And obviously, old age is taking the ones who do still live there. But again, it's definitely not an abandoned place. It's a busy, thriving place. And Jim, you've been involved in quite a long-term study of mammals in the area. Tell us about what you've learned from the radiation exposure. So we worked with our Belarusian colleagues. So the exclusion zone, about half is in Ukraine, half is in Belarus. And the Belarusians had a research institute there in their half of the exclusion zone. And every year after a fresh snowfall, they would go out and count mammal tracks.

25:46And they had about 35 different routes of 10 kilometers each, where they would count the mammal tracks crossing the route and identify the mammals. so we worked with them and we took their data and and calculated the radiation dose rate on each of those routes and what we were trying to find was is there a difference in the mammal densities in the more contaminated areas compared to the less contaminated areas and we got no result we got a negative result right which is an interesting result because it we couldn't see a difference in the mammal populations in the more contaminated parts of the zone compared to the less contaminated parts and that's that's over a whole range rabbits wolves wild boar roe deer yeah the other thing we could do was the belarussians did that in each of their four nature reserves including a unesco world heritage reserve on the border with poland and so we could compare the mammal densities in chernobyl with other nature reserves in the region and we found that the non-predatory mammals had no different population density to the other nature reserves the wolf population was seven times higher at chernobyl not because the radiation was helping the wolves but because the there's less hunting pressure on wolves in chernobyl than other areas yeah and what it says what does it say it It says human occupation of an ecosystem, hunting, fishing, forestry, agriculture, human occupation of an ecosystem is orders of magnitude worse than the world's worst nuclear accident.

27:24Yeah. Well, there's a huge amount to learn about rewilding, about the impact of humans. And I think that's brilliantly put. We've talked about the safety. Let's go on to this now. This is the atomic apple brandy that you make from apples grown around the Chernobyl. Tell us about it while I pour some out and we'll taste it. Is this in a shot glass or a tasting glass? I would put this in a tasting glass, I think. I have one each. So we worked in a town called Naradichi, which is in what we call the second zone. So it's a semi-abandoned area. So there's still people living there. There's still a school.

28:06There's shots in Narodichy. But there's no official use of agricultural land allowed. And we worked with our Ukrainian colleagues to say, this land can be used again. And as part of that, we did an experiment actually in the main exclusion zone near Chernobyl town. And we grew grain and measured the radioactivity in the grain. So this was 30 odd years after the accident. And we found that the grain was just slightly above the Ukrainian limit for contamination. It was actually below the EU limit, but it was above the Ukrainian limit. But when we took the grain and fermented and distilled it to make a kind of vodka, we couldn't find any Chernobyl radioactivity in the final product.

28:48We found carbon-14, which is in every spirit drink. It's in every food because it's natural. But we didn't find any cesium, any strontium, any plutonium. And so we set up a company called the Chernobyl Spirit Community Interest Company. So it's a social enterprise. And we work with a distillery in Ukraine. They go out. Vodka, it turned out, was complicated to make in Ukraine. So they're a distillery that specialise in fruit alcohols. So they go out every autumn to the abandoned areas, the semi-abandoned areas. So they buy apples from people, from people's gardens, from abandoned orchards. and then they ferment it and distill it to make an apple schnapps and an apple brandy aged in a Ukrainian oak.

29:35And we're biased, of course. We've compared it with the famous French Calvados, which is their apple brandy. And we think it's just as good, if not better. So the idea is that we produce this, we sell it online in the UK and now a few European countries. And our idea is that first to communicate the science about Chernobyl, but also to try and make some money to support those communities. So so far we've donated£50 ,000 to Ukraine and to those communities affected by the accident. Very nice, isn't it? I think it's fantastic, yeah. When I was there, there were lots of mature apple trees in Chernobyl and I was told that some people do still eat them.

30:17I did think. And I bet they ferment them as well. Quite likely, quite likely. But this is delicious. Thank you. So we'll put a link on the show notes if anyone wants to buy that. But what's the website address? It's www.atomicvodka.com. It's called Atomic is the brand name. Great, great brand name. Great. Look, thanks to our guest, Jim Smith from Portsmouth University, Matt Sparks. Do go and read Matt's report in New Scientist about the Chernobyl visit. And thanks to you for joining us. I'm Rowan Hooper. do follow and subscribe wherever you get your podcasts and we'll see you soon bye for now